1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (c) International Business Machines Corp., 2006
   4 *
   5 * Author: Artem Bityutskiy (Битюцкий Артём)
   6 */
   7
   8/*
   9 * The UBI Eraseblock Association (EBA) sub-system.
  10 *
  11 * This sub-system is responsible for I/O to/from logical eraseblock.
  12 *
  13 * Although in this implementation the EBA table is fully kept and managed in
  14 * RAM, which assumes poor scalability, it might be (partially) maintained on
  15 * flash in future implementations.
  16 *
  17 * The EBA sub-system implements per-logical eraseblock locking. Before
  18 * accessing a logical eraseblock it is locked for reading or writing. The
  19 * per-logical eraseblock locking is implemented by means of the lock tree. The
  20 * lock tree is an RB-tree which refers all the currently locked logical
  21 * eraseblocks. The lock tree elements are &struct ubi_ltree_entry objects.
  22 * They are indexed by (@vol_id, @lnum) pairs.
  23 *
  24 * EBA also maintains the global sequence counter which is incremented each
  25 * time a logical eraseblock is mapped to a physical eraseblock and it is
  26 * stored in the volume identifier header. This means that each VID header has
  27 * a unique sequence number. The sequence number is only increased an we assume
  28 * 64 bits is enough to never overflow.
  29 */
  30
  31#include <linux/slab.h>
  32#include <linux/crc32.h>
  33#include <linux/err.h>
  34#include "ubi.h"
  35
  36/**
  37 * struct ubi_eba_entry - structure encoding a single LEB -> PEB association
  38 * @pnum: the physical eraseblock number attached to the LEB
  39 *
  40 * This structure is encoding a LEB -> PEB association. Note that the LEB
  41 * number is not stored here, because it is the index used to access the
  42 * entries table.
  43 */
  44struct ubi_eba_entry {
  45	int pnum;
  46};
  47
  48/**
  49 * struct ubi_eba_table - LEB -> PEB association information
  50 * @entries: the LEB to PEB mapping (one entry per LEB).
  51 *
  52 * This structure is private to the EBA logic and should be kept here.
  53 * It is encoding the LEB to PEB association table, and is subject to
  54 * changes.
  55 */
  56struct ubi_eba_table {
  57	struct ubi_eba_entry *entries;
  58};
  59
  60/**
  61 * ubi_next_sqnum - get next sequence number.
  62 * @ubi: UBI device description object
  63 *
  64 * This function returns next sequence number to use, which is just the current
  65 * global sequence counter value. It also increases the global sequence
  66 * counter.
  67 */
  68unsigned long long ubi_next_sqnum(struct ubi_device *ubi)
  69{
  70	unsigned long long sqnum;
  71
  72	spin_lock(&ubi->ltree_lock);
  73	sqnum = ubi->global_sqnum++;
  74	spin_unlock(&ubi->ltree_lock);
  75
  76	return sqnum;
  77}
  78
  79/**
  80 * ubi_get_compat - get compatibility flags of a volume.
  81 * @ubi: UBI device description object
  82 * @vol_id: volume ID
  83 *
  84 * This function returns compatibility flags for an internal volume. User
  85 * volumes have no compatibility flags, so %0 is returned.
  86 */
  87static int ubi_get_compat(const struct ubi_device *ubi, int vol_id)
  88{
  89	if (vol_id == UBI_LAYOUT_VOLUME_ID)
  90		return UBI_LAYOUT_VOLUME_COMPAT;
  91	return 0;
  92}
  93
  94/**
  95 * ubi_eba_get_ldesc - get information about a LEB
  96 * @vol: volume description object
  97 * @lnum: logical eraseblock number
  98 * @ldesc: the LEB descriptor to fill
  99 *
 100 * Used to query information about a specific LEB.
 101 * It is currently only returning the physical position of the LEB, but will be
 102 * extended to provide more information.
 103 */
 104void ubi_eba_get_ldesc(struct ubi_volume *vol, int lnum,
 105		       struct ubi_eba_leb_desc *ldesc)
 106{
 107	ldesc->lnum = lnum;
 108	ldesc->pnum = vol->eba_tbl->entries[lnum].pnum;
 109}
 110
 111/**
 112 * ubi_eba_create_table - allocate a new EBA table and initialize it with all
 113 *			  LEBs unmapped
 114 * @vol: volume containing the EBA table to copy
 115 * @nentries: number of entries in the table
 116 *
 117 * Allocate a new EBA table and initialize it with all LEBs unmapped.
 118 * Returns a valid pointer if it succeed, an ERR_PTR() otherwise.
 119 */
 120struct ubi_eba_table *ubi_eba_create_table(struct ubi_volume *vol,
 121					   int nentries)
 122{
 123	struct ubi_eba_table *tbl;
 124	int err = -ENOMEM;
 125	int i;
 126
 127	tbl = kzalloc(sizeof(*tbl), GFP_KERNEL);
 128	if (!tbl)
 129		return ERR_PTR(-ENOMEM);
 130
 131	tbl->entries = kmalloc_array(nentries, sizeof(*tbl->entries),
 132				     GFP_KERNEL);
 133	if (!tbl->entries)
 134		goto err;
 135
 136	for (i = 0; i < nentries; i++)
 137		tbl->entries[i].pnum = UBI_LEB_UNMAPPED;
 138
 139	return tbl;
 140
 141err:
 142	kfree(tbl);
 143
 144	return ERR_PTR(err);
 145}
 146
 147/**
 148 * ubi_eba_destroy_table - destroy an EBA table
 149 * @tbl: the table to destroy
 150 *
 151 * Destroy an EBA table.
 152 */
 153void ubi_eba_destroy_table(struct ubi_eba_table *tbl)
 154{
 155	if (!tbl)
 156		return;
 157
 158	kfree(tbl->entries);
 159	kfree(tbl);
 160}
 161
 162/**
 163 * ubi_eba_copy_table - copy the EBA table attached to vol into another table
 164 * @vol: volume containing the EBA table to copy
 165 * @dst: destination
 166 * @nentries: number of entries to copy
 167 *
 168 * Copy the EBA table stored in vol into the one pointed by dst.
 169 */
 170void ubi_eba_copy_table(struct ubi_volume *vol, struct ubi_eba_table *dst,
 171			int nentries)
 172{
 173	struct ubi_eba_table *src;
 174	int i;
 175
 176	ubi_assert(dst && vol && vol->eba_tbl);
 177
 178	src = vol->eba_tbl;
 179
 180	for (i = 0; i < nentries; i++)
 181		dst->entries[i].pnum = src->entries[i].pnum;
 182}
 183
 184/**
 185 * ubi_eba_replace_table - assign a new EBA table to a volume
 186 * @vol: volume containing the EBA table to copy
 187 * @tbl: new EBA table
 188 *
 189 * Assign a new EBA table to the volume and release the old one.
 190 */
 191void ubi_eba_replace_table(struct ubi_volume *vol, struct ubi_eba_table *tbl)
 192{
 193	ubi_eba_destroy_table(vol->eba_tbl);
 194	vol->eba_tbl = tbl;
 195}
 196
 197/**
 198 * ltree_lookup - look up the lock tree.
 199 * @ubi: UBI device description object
 200 * @vol_id: volume ID
 201 * @lnum: logical eraseblock number
 202 *
 203 * This function returns a pointer to the corresponding &struct ubi_ltree_entry
 204 * object if the logical eraseblock is locked and %NULL if it is not.
 205 * @ubi->ltree_lock has to be locked.
 206 */
 207static struct ubi_ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
 208					    int lnum)
 209{
 210	struct rb_node *p;
 211
 212	p = ubi->ltree.rb_node;
 213	while (p) {
 214		struct ubi_ltree_entry *le;
 215
 216		le = rb_entry(p, struct ubi_ltree_entry, rb);
 217
 218		if (vol_id < le->vol_id)
 219			p = p->rb_left;
 220		else if (vol_id > le->vol_id)
 221			p = p->rb_right;
 222		else {
 223			if (lnum < le->lnum)
 224				p = p->rb_left;
 225			else if (lnum > le->lnum)
 226				p = p->rb_right;
 227			else
 228				return le;
 229		}
 230	}
 231
 232	return NULL;
 233}
 234
 235/**
 236 * ltree_add_entry - add new entry to the lock tree.
 237 * @ubi: UBI device description object
 238 * @vol_id: volume ID
 239 * @lnum: logical eraseblock number
 240 *
 241 * This function adds new entry for logical eraseblock (@vol_id, @lnum) to the
 242 * lock tree. If such entry is already there, its usage counter is increased.
 243 * Returns pointer to the lock tree entry or %-ENOMEM if memory allocation
 244 * failed.
 245 */
 246static struct ubi_ltree_entry *ltree_add_entry(struct ubi_device *ubi,
 247					       int vol_id, int lnum)
 248{
 249	struct ubi_ltree_entry *le, *le1, *le_free;
 250
 251	le = kmalloc(sizeof(struct ubi_ltree_entry), GFP_NOFS);
 252	if (!le)
 253		return ERR_PTR(-ENOMEM);
 254
 255	le->users = 0;
 256	init_rwsem(&le->mutex);
 257	le->vol_id = vol_id;
 258	le->lnum = lnum;
 259
 260	spin_lock(&ubi->ltree_lock);
 261	le1 = ltree_lookup(ubi, vol_id, lnum);
 262
 263	if (le1) {
 264		/*
 265		 * This logical eraseblock is already locked. The newly
 266		 * allocated lock entry is not needed.
 267		 */
 268		le_free = le;
 269		le = le1;
 270	} else {
 271		struct rb_node **p, *parent = NULL;
 272
 273		/*
 274		 * No lock entry, add the newly allocated one to the
 275		 * @ubi->ltree RB-tree.
 276		 */
 277		le_free = NULL;
 278
 279		p = &ubi->ltree.rb_node;
 280		while (*p) {
 281			parent = *p;
 282			le1 = rb_entry(parent, struct ubi_ltree_entry, rb);
 283
 284			if (vol_id < le1->vol_id)
 285				p = &(*p)->rb_left;
 286			else if (vol_id > le1->vol_id)
 287				p = &(*p)->rb_right;
 288			else {
 289				ubi_assert(lnum != le1->lnum);
 290				if (lnum < le1->lnum)
 291					p = &(*p)->rb_left;
 292				else
 293					p = &(*p)->rb_right;
 294			}
 295		}
 296
 297		rb_link_node(&le->rb, parent, p);
 298		rb_insert_color(&le->rb, &ubi->ltree);
 299	}
 300	le->users += 1;
 301	spin_unlock(&ubi->ltree_lock);
 302
 303	kfree(le_free);
 304	return le;
 305}
 306
 307/**
 308 * leb_read_lock - lock logical eraseblock for reading.
 309 * @ubi: UBI device description object
 310 * @vol_id: volume ID
 311 * @lnum: logical eraseblock number
 312 *
 313 * This function locks a logical eraseblock for reading. Returns zero in case
 314 * of success and a negative error code in case of failure.
 315 */
 316static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum)
 317{
 318	struct ubi_ltree_entry *le;
 319
 320	le = ltree_add_entry(ubi, vol_id, lnum);
 321	if (IS_ERR(le))
 322		return PTR_ERR(le);
 323	down_read(&le->mutex);
 324	return 0;
 325}
 326
 327/**
 328 * leb_read_unlock - unlock logical eraseblock.
 329 * @ubi: UBI device description object
 330 * @vol_id: volume ID
 331 * @lnum: logical eraseblock number
 332 */
 333static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
 334{
 335	struct ubi_ltree_entry *le;
 336
 337	spin_lock(&ubi->ltree_lock);
 338	le = ltree_lookup(ubi, vol_id, lnum);
 339	le->users -= 1;
 340	ubi_assert(le->users >= 0);
 341	up_read(&le->mutex);
 342	if (le->users == 0) {
 343		rb_erase(&le->rb, &ubi->ltree);
 344		kfree(le);
 345	}
 346	spin_unlock(&ubi->ltree_lock);
 347}
 348
 349/**
 350 * leb_write_lock - lock logical eraseblock for writing.
 351 * @ubi: UBI device description object
 352 * @vol_id: volume ID
 353 * @lnum: logical eraseblock number
 354 *
 355 * This function locks a logical eraseblock for writing. Returns zero in case
 356 * of success and a negative error code in case of failure.
 357 */
 358static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum)
 359{
 360	struct ubi_ltree_entry *le;
 361
 362	le = ltree_add_entry(ubi, vol_id, lnum);
 363	if (IS_ERR(le))
 364		return PTR_ERR(le);
 365	down_write(&le->mutex);
 366	return 0;
 367}
 368
 369/**
 370 * leb_write_trylock - try to lock logical eraseblock for writing.
 371 * @ubi: UBI device description object
 372 * @vol_id: volume ID
 373 * @lnum: logical eraseblock number
 374 *
 375 * This function locks a logical eraseblock for writing if there is no
 376 * contention and does nothing if there is contention. Returns %0 in case of
 377 * success, %1 in case of contention, and a negative error code in case of
 378 * failure.
 379 */
 380static int leb_write_trylock(struct ubi_device *ubi, int vol_id, int lnum)
 381{
 382	struct ubi_ltree_entry *le;
 383
 384	le = ltree_add_entry(ubi, vol_id, lnum);
 385	if (IS_ERR(le))
 386		return PTR_ERR(le);
 387	if (down_write_trylock(&le->mutex))
 388		return 0;
 389
 390	/* Contention, cancel */
 391	spin_lock(&ubi->ltree_lock);
 392	le->users -= 1;
 393	ubi_assert(le->users >= 0);
 394	if (le->users == 0) {
 395		rb_erase(&le->rb, &ubi->ltree);
 396		kfree(le);
 397	}
 398	spin_unlock(&ubi->ltree_lock);
 399
 400	return 1;
 401}
 402
 403/**
 404 * leb_write_unlock - unlock logical eraseblock.
 405 * @ubi: UBI device description object
 406 * @vol_id: volume ID
 407 * @lnum: logical eraseblock number
 408 */
 409static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
 410{
 411	struct ubi_ltree_entry *le;
 412
 413	spin_lock(&ubi->ltree_lock);
 414	le = ltree_lookup(ubi, vol_id, lnum);
 415	le->users -= 1;
 416	ubi_assert(le->users >= 0);
 417	up_write(&le->mutex);
 418	if (le->users == 0) {
 419		rb_erase(&le->rb, &ubi->ltree);
 420		kfree(le);
 421	}
 422	spin_unlock(&ubi->ltree_lock);
 423}
 424
 425/**
 426 * ubi_eba_is_mapped - check if a LEB is mapped.
 427 * @vol: volume description object
 428 * @lnum: logical eraseblock number
 429 *
 430 * This function returns true if the LEB is mapped, false otherwise.
 431 */
 432bool ubi_eba_is_mapped(struct ubi_volume *vol, int lnum)
 433{
 434	return vol->eba_tbl->entries[lnum].pnum >= 0;
 435}
 436
 437/**
 438 * ubi_eba_unmap_leb - un-map logical eraseblock.
 439 * @ubi: UBI device description object
 440 * @vol: volume description object
 441 * @lnum: logical eraseblock number
 442 *
 443 * This function un-maps logical eraseblock @lnum and schedules corresponding
 444 * physical eraseblock for erasure. Returns zero in case of success and a
 445 * negative error code in case of failure.
 446 */
 447int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
 448		      int lnum)
 449{
 450	int err, pnum, vol_id = vol->vol_id;
 451
 452	if (ubi->ro_mode)
 453		return -EROFS;
 454
 455	err = leb_write_lock(ubi, vol_id, lnum);
 456	if (err)
 457		return err;
 458
 459	pnum = vol->eba_tbl->entries[lnum].pnum;
 460	if (pnum < 0)
 461		/* This logical eraseblock is already unmapped */
 462		goto out_unlock;
 463
 464	dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);
 465
 466	down_read(&ubi->fm_eba_sem);
 467	vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED;
 468	up_read(&ubi->fm_eba_sem);
 469	err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 0);
 470
 471out_unlock:
 472	leb_write_unlock(ubi, vol_id, lnum);
 473	return err;
 474}
 475
 476#ifdef CONFIG_MTD_UBI_FASTMAP
 477/**
 478 * check_mapping - check and fixup a mapping
 479 * @ubi: UBI device description object
 480 * @vol: volume description object
 481 * @lnum: logical eraseblock number
 482 * @pnum: physical eraseblock number
 483 *
 484 * Checks whether a given mapping is valid. Fastmap cannot track LEB unmap
 485 * operations, if such an operation is interrupted the mapping still looks
 486 * good, but upon first read an ECC is reported to the upper layer.
 487 * Normaly during the full-scan at attach time this is fixed, for Fastmap
 488 * we have to deal with it while reading.
 489 * If the PEB behind a LEB shows this symthom we change the mapping to
 490 * %UBI_LEB_UNMAPPED and schedule the PEB for erasure.
 491 *
 492 * Returns 0 on success, negative error code in case of failure.
 493 */
 494static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 495			 int *pnum)
 496{
 497	int err;
 498	struct ubi_vid_io_buf *vidb;
 499	struct ubi_vid_hdr *vid_hdr;
 500
 501	if (!ubi->fast_attach)
 502		return 0;
 503
 504	if (!vol->checkmap || test_bit(lnum, vol->checkmap))
 505		return 0;
 506
 507	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
 508	if (!vidb)
 509		return -ENOMEM;
 510
 511	err = ubi_io_read_vid_hdr(ubi, *pnum, vidb, 0);
 512	if (err > 0 && err != UBI_IO_BITFLIPS) {
 513		int torture = 0;
 514
 515		switch (err) {
 516			case UBI_IO_FF:
 517			case UBI_IO_FF_BITFLIPS:
 518			case UBI_IO_BAD_HDR:
 519			case UBI_IO_BAD_HDR_EBADMSG:
 520				break;
 521			default:
 522				ubi_assert(0);
 523		}
 524
 525		if (err == UBI_IO_BAD_HDR_EBADMSG || err == UBI_IO_FF_BITFLIPS)
 526			torture = 1;
 527
 528		down_read(&ubi->fm_eba_sem);
 529		vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED;
 530		up_read(&ubi->fm_eba_sem);
 531		ubi_wl_put_peb(ubi, vol->vol_id, lnum, *pnum, torture);
 532
 533		*pnum = UBI_LEB_UNMAPPED;
 534	} else if (err < 0) {
 535		ubi_err(ubi, "unable to read VID header back from PEB %i: %i",
 536			*pnum, err);
 537
 538		goto out_free;
 539	} else {
 540		int found_vol_id, found_lnum;
 541
 542		ubi_assert(err == 0 || err == UBI_IO_BITFLIPS);
 543
 544		vid_hdr = ubi_get_vid_hdr(vidb);
 545		found_vol_id = be32_to_cpu(vid_hdr->vol_id);
 546		found_lnum = be32_to_cpu(vid_hdr->lnum);
 547
 548		if (found_lnum != lnum || found_vol_id != vol->vol_id) {
 549			ubi_err(ubi, "EBA mismatch! PEB %i is LEB %i:%i instead of LEB %i:%i",
 550				*pnum, found_vol_id, found_lnum, vol->vol_id, lnum);
 551			ubi_ro_mode(ubi);
 552			err = -EINVAL;
 553			goto out_free;
 554		}
 555	}
 556
 557	set_bit(lnum, vol->checkmap);
 558	err = 0;
 559
 560out_free:
 561	ubi_free_vid_buf(vidb);
 562
 563	return err;
 564}
 565#else
 566static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 567		  int *pnum)
 568{
 569	return 0;
 570}
 571#endif
 572
 573/**
 574 * ubi_eba_read_leb - read data.
 575 * @ubi: UBI device description object
 576 * @vol: volume description object
 577 * @lnum: logical eraseblock number
 578 * @buf: buffer to store the read data
 579 * @offset: offset from where to read
 580 * @len: how many bytes to read
 581 * @check: data CRC check flag
 582 *
 583 * If the logical eraseblock @lnum is unmapped, @buf is filled with 0xFF
 584 * bytes. The @check flag only makes sense for static volumes and forces
 585 * eraseblock data CRC checking.
 586 *
 587 * In case of success this function returns zero. In case of a static volume,
 588 * if data CRC mismatches - %-EBADMSG is returned. %-EBADMSG may also be
 589 * returned for any volume type if an ECC error was detected by the MTD device
 590 * driver. Other negative error cored may be returned in case of other errors.
 591 */
 592int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 593		     void *buf, int offset, int len, int check)
 594{
 595	int err, pnum, scrub = 0, vol_id = vol->vol_id;
 596	struct ubi_vid_io_buf *vidb;
 597	struct ubi_vid_hdr *vid_hdr;
 598	uint32_t crc;
 599
 600	err = leb_read_lock(ubi, vol_id, lnum);
 601	if (err)
 602		return err;
 603
 604	pnum = vol->eba_tbl->entries[lnum].pnum;
 605	if (pnum >= 0) {
 606		err = check_mapping(ubi, vol, lnum, &pnum);
 607		if (err < 0)
 608			goto out_unlock;
 609	}
 610
 611	if (pnum == UBI_LEB_UNMAPPED) {
 612		/*
 613		 * The logical eraseblock is not mapped, fill the whole buffer
 614		 * with 0xFF bytes. The exception is static volumes for which
 615		 * it is an error to read unmapped logical eraseblocks.
 616		 */
 617		dbg_eba("read %d bytes from offset %d of LEB %d:%d (unmapped)",
 618			len, offset, vol_id, lnum);
 619		leb_read_unlock(ubi, vol_id, lnum);
 620		ubi_assert(vol->vol_type != UBI_STATIC_VOLUME);
 621		memset(buf, 0xFF, len);
 622		return 0;
 623	}
 624
 625	dbg_eba("read %d bytes from offset %d of LEB %d:%d, PEB %d",
 626		len, offset, vol_id, lnum, pnum);
 627
 628	if (vol->vol_type == UBI_DYNAMIC_VOLUME)
 629		check = 0;
 630
 631retry:
 632	if (check) {
 633		vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
 634		if (!vidb) {
 635			err = -ENOMEM;
 636			goto out_unlock;
 637		}
 638
 639		vid_hdr = ubi_get_vid_hdr(vidb);
 640
 641		err = ubi_io_read_vid_hdr(ubi, pnum, vidb, 1);
 642		if (err && err != UBI_IO_BITFLIPS) {
 643			if (err > 0) {
 644				/*
 645				 * The header is either absent or corrupted.
 646				 * The former case means there is a bug -
 647				 * switch to read-only mode just in case.
 648				 * The latter case means a real corruption - we
 649				 * may try to recover data. FIXME: but this is
 650				 * not implemented.
 651				 */
 652				if (err == UBI_IO_BAD_HDR_EBADMSG ||
 653				    err == UBI_IO_BAD_HDR) {
 654					ubi_warn(ubi, "corrupted VID header at PEB %d, LEB %d:%d",
 655						 pnum, vol_id, lnum);
 656					err = -EBADMSG;
 657				} else {
 658					/*
 659					 * Ending up here in the non-Fastmap case
 660					 * is a clear bug as the VID header had to
 661					 * be present at scan time to have it referenced.
 662					 * With fastmap the story is more complicated.
 663					 * Fastmap has the mapping info without the need
 664					 * of a full scan. So the LEB could have been
 665					 * unmapped, Fastmap cannot know this and keeps
 666					 * the LEB referenced.
 667					 * This is valid and works as the layer above UBI
 668					 * has to do bookkeeping about used/referenced
 669					 * LEBs in any case.
 670					 */
 671					if (ubi->fast_attach) {
 672						err = -EBADMSG;
 673					} else {
 674						err = -EINVAL;
 675						ubi_ro_mode(ubi);
 676					}
 677				}
 678			}
 679			goto out_free;
 680		} else if (err == UBI_IO_BITFLIPS)
 681			scrub = 1;
 682
 683		ubi_assert(lnum < be32_to_cpu(vid_hdr->used_ebs));
 684		ubi_assert(len == be32_to_cpu(vid_hdr->data_size));
 685
 686		crc = be32_to_cpu(vid_hdr->data_crc);
 687		ubi_free_vid_buf(vidb);
 688	}
 689
 690	err = ubi_io_read_data(ubi, buf, pnum, offset, len);
 691	if (err) {
 692		if (err == UBI_IO_BITFLIPS)
 693			scrub = 1;
 694		else if (mtd_is_eccerr(err)) {
 695			if (vol->vol_type == UBI_DYNAMIC_VOLUME)
 696				goto out_unlock;
 697			scrub = 1;
 698			if (!check) {
 699				ubi_msg(ubi, "force data checking");
 700				check = 1;
 701				goto retry;
 702			}
 703		} else
 704			goto out_unlock;
 705	}
 706
 707	if (check) {
 708		uint32_t crc1 = crc32(UBI_CRC32_INIT, buf, len);
 709		if (crc1 != crc) {
 710			ubi_warn(ubi, "CRC error: calculated %#08x, must be %#08x",
 711				 crc1, crc);
 712			err = -EBADMSG;
 713			goto out_unlock;
 714		}
 715	}
 716
 717	if (scrub)
 718		err = ubi_wl_scrub_peb(ubi, pnum);
 719
 720	leb_read_unlock(ubi, vol_id, lnum);
 721	return err;
 722
 723out_free:
 724	ubi_free_vid_buf(vidb);
 725out_unlock:
 726	leb_read_unlock(ubi, vol_id, lnum);
 727	return err;
 728}
 729
 730/**
 731 * ubi_eba_read_leb_sg - read data into a scatter gather list.
 732 * @ubi: UBI device description object
 733 * @vol: volume description object
 734 * @lnum: logical eraseblock number
 735 * @sgl: UBI scatter gather list to store the read data
 736 * @offset: offset from where to read
 737 * @len: how many bytes to read
 738 * @check: data CRC check flag
 739 *
 740 * This function works exactly like ubi_eba_read_leb(). But instead of
 741 * storing the read data into a buffer it writes to an UBI scatter gather
 742 * list.
 743 */
 744int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol,
 745			struct ubi_sgl *sgl, int lnum, int offset, int len,
 746			int check)
 747{
 748	int to_read;
 749	int ret;
 750	struct scatterlist *sg;
 751
 752	for (;;) {
 753		ubi_assert(sgl->list_pos < UBI_MAX_SG_COUNT);
 754		sg = &sgl->sg[sgl->list_pos];
 755		if (len < sg->length - sgl->page_pos)
 756			to_read = len;
 757		else
 758			to_read = sg->length - sgl->page_pos;
 759
 760		ret = ubi_eba_read_leb(ubi, vol, lnum,
 761				       sg_virt(sg) + sgl->page_pos, offset,
 762				       to_read, check);
 763		if (ret < 0)
 764			return ret;
 765
 766		offset += to_read;
 767		len -= to_read;
 768		if (!len) {
 769			sgl->page_pos += to_read;
 770			if (sgl->page_pos == sg->length) {
 771				sgl->list_pos++;
 772				sgl->page_pos = 0;
 773			}
 774
 775			break;
 776		}
 777
 778		sgl->list_pos++;
 779		sgl->page_pos = 0;
 780	}
 781
 782	return ret;
 783}
 784
 785/**
 786 * try_recover_peb - try to recover from write failure.
 787 * @vol: volume description object
 788 * @pnum: the physical eraseblock to recover
 789 * @lnum: logical eraseblock number
 790 * @buf: data which was not written because of the write failure
 791 * @offset: offset of the failed write
 792 * @len: how many bytes should have been written
 793 * @vidb: VID buffer
 794 * @retry: whether the caller should retry in case of failure
 795 *
 796 * This function is called in case of a write failure and moves all good data
 797 * from the potentially bad physical eraseblock to a good physical eraseblock.
 798 * This function also writes the data which was not written due to the failure.
 799 * Returns 0 in case of success, and a negative error code in case of failure.
 800 * In case of failure, the %retry parameter is set to false if this is a fatal
 801 * error (retrying won't help), and true otherwise.
 802 */
 803static int try_recover_peb(struct ubi_volume *vol, int pnum, int lnum,
 804			   const void *buf, int offset, int len,
 805			   struct ubi_vid_io_buf *vidb, bool *retry)
 806{
 807	struct ubi_device *ubi = vol->ubi;
 808	struct ubi_vid_hdr *vid_hdr;
 809	int new_pnum, err, vol_id = vol->vol_id, data_size;
 810	uint32_t crc;
 811
 812	*retry = false;
 813
 814	new_pnum = ubi_wl_get_peb(ubi);
 815	if (new_pnum < 0) {
 816		err = new_pnum;
 817		goto out_put;
 818	}
 819
 820	ubi_msg(ubi, "recover PEB %d, move data to PEB %d",
 821		pnum, new_pnum);
 822
 823	err = ubi_io_read_vid_hdr(ubi, pnum, vidb, 1);
 824	if (err && err != UBI_IO_BITFLIPS) {
 825		if (err > 0)
 826			err = -EIO;
 827		goto out_put;
 828	}
 829
 830	vid_hdr = ubi_get_vid_hdr(vidb);
 831	ubi_assert(vid_hdr->vol_type == UBI_VID_DYNAMIC);
 832
 833	mutex_lock(&ubi->buf_mutex);
 834	memset(ubi->peb_buf + offset, 0xFF, len);
 835
 836	/* Read everything before the area where the write failure happened */
 837	if (offset > 0) {
 838		err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, offset);
 839		if (err && err != UBI_IO_BITFLIPS)
 840			goto out_unlock;
 841	}
 842
 843	*retry = true;
 844
 845	memcpy(ubi->peb_buf + offset, buf, len);
 846
 847	data_size = offset + len;
 848	crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size);
 849	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
 850	vid_hdr->copy_flag = 1;
 851	vid_hdr->data_size = cpu_to_be32(data_size);
 852	vid_hdr->data_crc = cpu_to_be32(crc);
 853	err = ubi_io_write_vid_hdr(ubi, new_pnum, vidb);
 854	if (err)
 855		goto out_unlock;
 856
 857	err = ubi_io_write_data(ubi, ubi->peb_buf, new_pnum, 0, data_size);
 858
 859out_unlock:
 860	mutex_unlock(&ubi->buf_mutex);
 861
 862	if (!err)
 863		vol->eba_tbl->entries[lnum].pnum = new_pnum;
 864
 865out_put:
 866	up_read(&ubi->fm_eba_sem);
 867
 868	if (!err) {
 869		ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
 870		ubi_msg(ubi, "data was successfully recovered");
 871	} else if (new_pnum >= 0) {
 872		/*
 873		 * Bad luck? This physical eraseblock is bad too? Crud. Let's
 874		 * try to get another one.
 875		 */
 876		ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1);
 877		ubi_warn(ubi, "failed to write to PEB %d", new_pnum);
 878	}
 879
 880	return err;
 881}
 882
 883/**
 884 * recover_peb - recover from write failure.
 885 * @ubi: UBI device description object
 886 * @pnum: the physical eraseblock to recover
 887 * @vol_id: volume ID
 888 * @lnum: logical eraseblock number
 889 * @buf: data which was not written because of the write failure
 890 * @offset: offset of the failed write
 891 * @len: how many bytes should have been written
 892 *
 893 * This function is called in case of a write failure and moves all good data
 894 * from the potentially bad physical eraseblock to a good physical eraseblock.
 895 * This function also writes the data which was not written due to the failure.
 896 * Returns 0 in case of success, and a negative error code in case of failure.
 897 * This function tries %UBI_IO_RETRIES before giving up.
 898 */
 899static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
 900		       const void *buf, int offset, int len)
 901{
 902	int err, idx = vol_id2idx(ubi, vol_id), tries;
 903	struct ubi_volume *vol = ubi->volumes[idx];
 904	struct ubi_vid_io_buf *vidb;
 905
 906	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
 907	if (!vidb)
 908		return -ENOMEM;
 909
 910	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
 911		bool retry;
 912
 913		err = try_recover_peb(vol, pnum, lnum, buf, offset, len, vidb,
 914				      &retry);
 915		if (!err || !retry)
 916			break;
 917
 918		ubi_msg(ubi, "try again");
 919	}
 920
 921	ubi_free_vid_buf(vidb);
 922
 923	return err;
 924}
 925
 926/**
 927 * try_write_vid_and_data - try to write VID header and data to a new PEB.
 928 * @vol: volume description object
 929 * @lnum: logical eraseblock number
 930 * @vidb: the VID buffer to write
 931 * @buf: buffer containing the data
 932 * @offset: where to start writing data
 933 * @len: how many bytes should be written
 934 *
 935 * This function tries to write VID header and data belonging to logical
 936 * eraseblock @lnum of volume @vol to a new physical eraseblock. Returns zero
 937 * in case of success and a negative error code in case of failure.
 938 * In case of error, it is possible that something was still written to the
 939 * flash media, but may be some garbage.
 940 */
 941static int try_write_vid_and_data(struct ubi_volume *vol, int lnum,
 942				  struct ubi_vid_io_buf *vidb, const void *buf,
 943				  int offset, int len)
 944{
 945	struct ubi_device *ubi = vol->ubi;
 946	int pnum, opnum, err, err2, vol_id = vol->vol_id;
 947
 948	pnum = ubi_wl_get_peb(ubi);
 949	if (pnum < 0) {
 950		err = pnum;
 951		goto out_put;
 952	}
 953
 954	opnum = vol->eba_tbl->entries[lnum].pnum;
 955
 956	dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
 957		len, offset, vol_id, lnum, pnum);
 958
 959	err = ubi_io_write_vid_hdr(ubi, pnum, vidb);
 960	if (err) {
 961		ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
 962			 vol_id, lnum, pnum);
 963		goto out_put;
 964	}
 965
 966	if (len) {
 967		err = ubi_io_write_data(ubi, buf, pnum, offset, len);
 968		if (err) {
 969			ubi_warn(ubi,
 970				 "failed to write %d bytes at offset %d of LEB %d:%d, PEB %d",
 971				 len, offset, vol_id, lnum, pnum);
 972			goto out_put;
 973		}
 974	}
 975
 976	vol->eba_tbl->entries[lnum].pnum = pnum;
 977
 978out_put:
 979	up_read(&ubi->fm_eba_sem);
 980
 981	if (err && pnum >= 0) {
 982		err2 = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
 983		if (err2) {
 984			ubi_warn(ubi, "failed to return physical eraseblock %d, error %d",
 985				 pnum, err2);
 986		}
 987	} else if (!err && opnum >= 0) {
 988		err2 = ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0);
 989		if (err2) {
 990			ubi_warn(ubi, "failed to return physical eraseblock %d, error %d",
 991				 opnum, err2);
 992		}
 993	}
 994
 995	return err;
 996}
 997
 998/**
 999 * ubi_eba_write_leb - write data to dynamic volume.
1000 * @ubi: UBI device description object
1001 * @vol: volume description object
1002 * @lnum: logical eraseblock number
1003 * @buf: the data to write
1004 * @offset: offset within the logical eraseblock where to write
1005 * @len: how many bytes to write
1006 *
1007 * This function writes data to logical eraseblock @lnum of a dynamic volume
1008 * @vol. Returns zero in case of success and a negative error code in case
1009 * of failure. In case of error, it is possible that something was still
1010 * written to the flash media, but may be some garbage.
1011 * This function retries %UBI_IO_RETRIES times before giving up.
1012 */
1013int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
1014		      const void *buf, int offset, int len)
1015{
1016	int err, pnum, tries, vol_id = vol->vol_id;
1017	struct ubi_vid_io_buf *vidb;
1018	struct ubi_vid_hdr *vid_hdr;
1019
1020	if (ubi->ro_mode)
1021		return -EROFS;
1022
1023	err = leb_write_lock(ubi, vol_id, lnum);
1024	if (err)
1025		return err;
1026
1027	pnum = vol->eba_tbl->entries[lnum].pnum;
1028	if (pnum >= 0) {
1029		err = check_mapping(ubi, vol, lnum, &pnum);
1030		if (err < 0)
1031			goto out;
1032	}
1033
1034	if (pnum >= 0) {
1035		dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
1036			len, offset, vol_id, lnum, pnum);
1037
1038		err = ubi_io_write_data(ubi, buf, pnum, offset, len);
1039		if (err) {
1040			ubi_warn(ubi, "failed to write data to PEB %d", pnum);
1041			if (err == -EIO && ubi->bad_allowed)
1042				err = recover_peb(ubi, pnum, vol_id, lnum, buf,
1043						  offset, len);
1044		}
1045
1046		goto out;
1047	}
1048
1049	/*
1050	 * The logical eraseblock is not mapped. We have to get a free physical
1051	 * eraseblock and write the volume identifier header there first.
1052	 */
1053	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1054	if (!vidb) {
1055		leb_write_unlock(ubi, vol_id, lnum);
1056		return -ENOMEM;
1057	}
1058
1059	vid_hdr = ubi_get_vid_hdr(vidb);
1060
1061	vid_hdr->vol_type = UBI_VID_DYNAMIC;
1062	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1063	vid_hdr->vol_id = cpu_to_be32(vol_id);
1064	vid_hdr->lnum = cpu_to_be32(lnum);
1065	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1066	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1067
1068	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1069		err = try_write_vid_and_data(vol, lnum, vidb, buf, offset, len);
1070		if (err != -EIO || !ubi->bad_allowed)
1071			break;
1072
1073		/*
1074		 * Fortunately, this is the first write operation to this
1075		 * physical eraseblock, so just put it and request a new one.
1076		 * We assume that if this physical eraseblock went bad, the
1077		 * erase code will handle that.
1078		 */
1079		vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1080		ubi_msg(ubi, "try another PEB");
1081	}
1082
1083	ubi_free_vid_buf(vidb);
1084
1085out:
1086	if (err)
1087		ubi_ro_mode(ubi);
1088
1089	leb_write_unlock(ubi, vol_id, lnum);
1090
1091	return err;
1092}
1093
1094/**
1095 * ubi_eba_write_leb_st - write data to static volume.
1096 * @ubi: UBI device description object
1097 * @vol: volume description object
1098 * @lnum: logical eraseblock number
1099 * @buf: data to write
1100 * @len: how many bytes to write
1101 * @used_ebs: how many logical eraseblocks will this volume contain
1102 *
1103 * This function writes data to logical eraseblock @lnum of static volume
1104 * @vol. The @used_ebs argument should contain total number of logical
1105 * eraseblock in this static volume.
1106 *
1107 * When writing to the last logical eraseblock, the @len argument doesn't have
1108 * to be aligned to the minimal I/O unit size. Instead, it has to be equivalent
1109 * to the real data size, although the @buf buffer has to contain the
1110 * alignment. In all other cases, @len has to be aligned.
1111 *
1112 * It is prohibited to write more than once to logical eraseblocks of static
1113 * volumes. This function returns zero in case of success and a negative error
1114 * code in case of failure.
1115 */
1116int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
1117			 int lnum, const void *buf, int len, int used_ebs)
1118{
1119	int err, tries, data_size = len, vol_id = vol->vol_id;
1120	struct ubi_vid_io_buf *vidb;
1121	struct ubi_vid_hdr *vid_hdr;
1122	uint32_t crc;
1123
1124	if (ubi->ro_mode)
1125		return -EROFS;
1126
1127	if (lnum == used_ebs - 1)
1128		/* If this is the last LEB @len may be unaligned */
1129		len = ALIGN(data_size, ubi->min_io_size);
1130	else
1131		ubi_assert(!(len & (ubi->min_io_size - 1)));
1132
1133	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1134	if (!vidb)
1135		return -ENOMEM;
1136
1137	vid_hdr = ubi_get_vid_hdr(vidb);
1138
1139	err = leb_write_lock(ubi, vol_id, lnum);
1140	if (err)
1141		goto out;
1142
1143	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1144	vid_hdr->vol_id = cpu_to_be32(vol_id);
1145	vid_hdr->lnum = cpu_to_be32(lnum);
1146	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1147	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1148
1149	crc = crc32(UBI_CRC32_INIT, buf, data_size);
1150	vid_hdr->vol_type = UBI_VID_STATIC;
1151	vid_hdr->data_size = cpu_to_be32(data_size);
1152	vid_hdr->used_ebs = cpu_to_be32(used_ebs);
1153	vid_hdr->data_crc = cpu_to_be32(crc);
1154
1155	ubi_assert(vol->eba_tbl->entries[lnum].pnum < 0);
1156
1157	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1158		err = try_write_vid_and_data(vol, lnum, vidb, buf, 0, len);
1159		if (err != -EIO || !ubi->bad_allowed)
1160			break;
1161
1162		vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1163		ubi_msg(ubi, "try another PEB");
1164	}
1165
1166	if (err)
1167		ubi_ro_mode(ubi);
1168
1169	leb_write_unlock(ubi, vol_id, lnum);
1170
1171out:
1172	ubi_free_vid_buf(vidb);
1173
1174	return err;
1175}
1176
1177/*
1178 * ubi_eba_atomic_leb_change - change logical eraseblock atomically.
1179 * @ubi: UBI device description object
1180 * @vol: volume description object
1181 * @lnum: logical eraseblock number
1182 * @buf: data to write
1183 * @len: how many bytes to write
1184 *
1185 * This function changes the contents of a logical eraseblock atomically. @buf
1186 * has to contain new logical eraseblock data, and @len - the length of the
1187 * data, which has to be aligned. This function guarantees that in case of an
1188 * unclean reboot the old contents is preserved. Returns zero in case of
1189 * success and a negative error code in case of failure.
1190 *
1191 * UBI reserves one LEB for the "atomic LEB change" operation, so only one
1192 * LEB change may be done at a time. This is ensured by @ubi->alc_mutex.
1193 */
1194int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
1195			      int lnum, const void *buf, int len)
1196{
1197	int err, tries, vol_id = vol->vol_id;
1198	struct ubi_vid_io_buf *vidb;
1199	struct ubi_vid_hdr *vid_hdr;
1200	uint32_t crc;
1201
1202	if (ubi->ro_mode)
1203		return -EROFS;
1204
1205	if (len == 0) {
1206		/*
1207		 * Special case when data length is zero. In this case the LEB
1208		 * has to be unmapped and mapped somewhere else.
1209		 */
1210		err = ubi_eba_unmap_leb(ubi, vol, lnum);
1211		if (err)
1212			return err;
1213		return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
1214	}
1215
1216	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1217	if (!vidb)
1218		return -ENOMEM;
1219
1220	vid_hdr = ubi_get_vid_hdr(vidb);
1221
1222	mutex_lock(&ubi->alc_mutex);
1223	err = leb_write_lock(ubi, vol_id, lnum);
1224	if (err)
1225		goto out_mutex;
1226
1227	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1228	vid_hdr->vol_id = cpu_to_be32(vol_id);
1229	vid_hdr->lnum = cpu_to_be32(lnum);
1230	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1231	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1232
1233	crc = crc32(UBI_CRC32_INIT, buf, len);
1234	vid_hdr->vol_type = UBI_VID_DYNAMIC;
1235	vid_hdr->data_size = cpu_to_be32(len);
1236	vid_hdr->copy_flag = 1;
1237	vid_hdr->data_crc = cpu_to_be32(crc);
1238
1239	dbg_eba("change LEB %d:%d", vol_id, lnum);
1240
1241	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1242		err = try_write_vid_and_data(vol, lnum, vidb, buf, 0, len);
1243		if (err != -EIO || !ubi->bad_allowed)
1244			break;
1245
1246		vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1247		ubi_msg(ubi, "try another PEB");
1248	}
1249
1250	/*
1251	 * This flash device does not admit of bad eraseblocks or
1252	 * something nasty and unexpected happened. Switch to read-only
1253	 * mode just in case.
1254	 */
1255	if (err)
1256		ubi_ro_mode(ubi);
1257
1258	leb_write_unlock(ubi, vol_id, lnum);
1259
1260out_mutex:
1261	mutex_unlock(&ubi->alc_mutex);
1262	ubi_free_vid_buf(vidb);
1263	return err;
1264}
1265
1266/**
1267 * is_error_sane - check whether a read error is sane.
1268 * @err: code of the error happened during reading
1269 *
1270 * This is a helper function for 'ubi_eba_copy_leb()' which is called when we
1271 * cannot read data from the target PEB (an error @err happened). If the error
1272 * code is sane, then we treat this error as non-fatal. Otherwise the error is
1273 * fatal and UBI will be switched to R/O mode later.
1274 *
1275 * The idea is that we try not to switch to R/O mode if the read error is
1276 * something which suggests there was a real read problem. E.g., %-EIO. Or a
1277 * memory allocation failed (-%ENOMEM). Otherwise, it is safer to switch to R/O
1278 * mode, simply because we do not know what happened at the MTD level, and we
1279 * cannot handle this. E.g., the underlying driver may have become crazy, and
1280 * it is safer to switch to R/O mode to preserve the data.
1281 *
1282 * And bear in mind, this is about reading from the target PEB, i.e. the PEB
1283 * which we have just written.
1284 */
1285static int is_error_sane(int err)
1286{
1287	if (err == -EIO || err == -ENOMEM || err == UBI_IO_BAD_HDR ||
1288	    err == UBI_IO_BAD_HDR_EBADMSG || err == -ETIMEDOUT)
1289		return 0;
1290	return 1;
1291}
1292
1293/**
1294 * ubi_eba_copy_leb - copy logical eraseblock.
1295 * @ubi: UBI device description object
1296 * @from: physical eraseblock number from where to copy
1297 * @to: physical eraseblock number where to copy
1298 * @vidb: data structure from where the VID header is derived
1299 *
1300 * This function copies logical eraseblock from physical eraseblock @from to
1301 * physical eraseblock @to. The @vid_hdr buffer may be changed by this
1302 * function. Returns:
1303 *   o %0 in case of success;
1304 *   o %MOVE_CANCEL_RACE, %MOVE_TARGET_WR_ERR, %MOVE_TARGET_BITFLIPS, etc;
1305 *   o a negative error code in case of failure.
1306 */
1307int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
1308		     struct ubi_vid_io_buf *vidb)
1309{
1310	int err, vol_id, lnum, data_size, aldata_size, idx;
1311	struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1312	struct ubi_volume *vol;
1313	uint32_t crc;
1314
1315	ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));
1316
1317	vol_id = be32_to_cpu(vid_hdr->vol_id);
1318	lnum = be32_to_cpu(vid_hdr->lnum);
1319
1320	dbg_wl("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to);
1321
1322	if (vid_hdr->vol_type == UBI_VID_STATIC) {
1323		data_size = be32_to_cpu(vid_hdr->data_size);
1324		aldata_size = ALIGN(data_size, ubi->min_io_size);
1325	} else
1326		data_size = aldata_size =
1327			    ubi->leb_size - be32_to_cpu(vid_hdr->data_pad);
1328
1329	idx = vol_id2idx(ubi, vol_id);
1330	spin_lock(&ubi->volumes_lock);
1331	/*
1332	 * Note, we may race with volume deletion, which means that the volume
1333	 * this logical eraseblock belongs to might be being deleted. Since the
1334	 * volume deletion un-maps all the volume's logical eraseblocks, it will
1335	 * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
1336	 */
1337	vol = ubi->volumes[idx];
1338	spin_unlock(&ubi->volumes_lock);
1339	if (!vol) {
1340		/* No need to do further work, cancel */
1341		dbg_wl("volume %d is being removed, cancel", vol_id);
1342		return MOVE_CANCEL_RACE;
1343	}
1344
1345	/*
1346	 * We do not want anybody to write to this logical eraseblock while we
1347	 * are moving it, so lock it.
1348	 *
1349	 * Note, we are using non-waiting locking here, because we cannot sleep
1350	 * on the LEB, since it may cause deadlocks. Indeed, imagine a task is
1351	 * unmapping the LEB which is mapped to the PEB we are going to move
1352	 * (@from). This task locks the LEB and goes sleep in the
1353	 * 'ubi_wl_put_peb()' function on the @ubi->move_mutex. In turn, we are
1354	 * holding @ubi->move_mutex and go sleep on the LEB lock. So, if the
1355	 * LEB is already locked, we just do not move it and return
1356	 * %MOVE_RETRY. Note, we do not return %MOVE_CANCEL_RACE here because
1357	 * we do not know the reasons of the contention - it may be just a
1358	 * normal I/O on this LEB, so we want to re-try.
1359	 */
1360	err = leb_write_trylock(ubi, vol_id, lnum);
1361	if (err) {
1362		dbg_wl("contention on LEB %d:%d, cancel", vol_id, lnum);
1363		return MOVE_RETRY;
1364	}
1365
1366	/*
1367	 * The LEB might have been put meanwhile, and the task which put it is
1368	 * probably waiting on @ubi->move_mutex. No need to continue the work,
1369	 * cancel it.
1370	 */
1371	if (vol->eba_tbl->entries[lnum].pnum != from) {
1372		dbg_wl("LEB %d:%d is no longer mapped to PEB %d, mapped to PEB %d, cancel",
1373		       vol_id, lnum, from, vol->eba_tbl->entries[lnum].pnum);
1374		err = MOVE_CANCEL_RACE;
1375		goto out_unlock_leb;
1376	}
1377
1378	/*
1379	 * OK, now the LEB is locked and we can safely start moving it. Since
1380	 * this function utilizes the @ubi->peb_buf buffer which is shared
1381	 * with some other functions - we lock the buffer by taking the
1382	 * @ubi->buf_mutex.
1383	 */
1384	mutex_lock(&ubi->buf_mutex);
1385	dbg_wl("read %d bytes of data", aldata_size);
1386	err = ubi_io_read_data(ubi, ubi->peb_buf, from, 0, aldata_size);
1387	if (err && err != UBI_IO_BITFLIPS) {
1388		ubi_warn(ubi, "error %d while reading data from PEB %d",
1389			 err, from);
1390		err = MOVE_SOURCE_RD_ERR;
1391		goto out_unlock_buf;
1392	}
1393
1394	/*
1395	 * Now we have got to calculate how much data we have to copy. In
1396	 * case of a static volume it is fairly easy - the VID header contains
1397	 * the data size. In case of a dynamic volume it is more difficult - we
1398	 * have to read the contents, cut 0xFF bytes from the end and copy only
1399	 * the first part. We must do this to avoid writing 0xFF bytes as it
1400	 * may have some side-effects. And not only this. It is important not
1401	 * to include those 0xFFs to CRC because later the they may be filled
1402	 * by data.
1403	 */
1404	if (vid_hdr->vol_type == UBI_VID_DYNAMIC)
1405		aldata_size = data_size =
1406			ubi_calc_data_len(ubi, ubi->peb_buf, data_size);
1407
1408	cond_resched();
1409	crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size);
1410	cond_resched();
1411
1412	/*
1413	 * It may turn out to be that the whole @from physical eraseblock
1414	 * contains only 0xFF bytes. Then we have to only write the VID header
1415	 * and do not write any data. This also means we should not set
1416	 * @vid_hdr->copy_flag, @vid_hdr->data_size, and @vid_hdr->data_crc.
1417	 */
1418	if (data_size > 0) {
1419		vid_hdr->copy_flag = 1;
1420		vid_hdr->data_size = cpu_to_be32(data_size);
1421		vid_hdr->data_crc = cpu_to_be32(crc);
1422	}
1423	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1424
1425	err = ubi_io_write_vid_hdr(ubi, to, vidb);
1426	if (err) {
1427		if (err == -EIO)
1428			err = MOVE_TARGET_WR_ERR;
1429		goto out_unlock_buf;
1430	}
1431
1432	cond_resched();
1433
1434	/* Read the VID header back and check if it was written correctly */
1435	err = ubi_io_read_vid_hdr(ubi, to, vidb, 1);
1436	if (err) {
1437		if (err != UBI_IO_BITFLIPS) {
1438			ubi_warn(ubi, "error %d while reading VID header back from PEB %d",
1439				 err, to);
1440			if (is_error_sane(err))
1441				err = MOVE_TARGET_RD_ERR;
1442		} else
1443			err = MOVE_TARGET_BITFLIPS;
1444		goto out_unlock_buf;
1445	}
1446
1447	if (data_size > 0) {
1448		err = ubi_io_write_data(ubi, ubi->peb_buf, to, 0, aldata_size);
1449		if (err) {
1450			if (err == -EIO)
1451				err = MOVE_TARGET_WR_ERR;
1452			goto out_unlock_buf;
1453		}
1454
1455		cond_resched();
1456	}
1457
1458	ubi_assert(vol->eba_tbl->entries[lnum].pnum == from);
 
 
 
 
 
 
1459	vol->eba_tbl->entries[lnum].pnum = to;
 
1460
1461out_unlock_buf:
1462	mutex_unlock(&ubi->buf_mutex);
1463out_unlock_leb:
1464	leb_write_unlock(ubi, vol_id, lnum);
1465	return err;
1466}
1467
1468/**
1469 * print_rsvd_warning - warn about not having enough reserved PEBs.
1470 * @ubi: UBI device description object
1471 * @ai: UBI attach info object
1472 *
1473 * This is a helper function for 'ubi_eba_init()' which is called when UBI
1474 * cannot reserve enough PEBs for bad block handling. This function makes a
1475 * decision whether we have to print a warning or not. The algorithm is as
1476 * follows:
1477 *   o if this is a new UBI image, then just print the warning
1478 *   o if this is an UBI image which has already been used for some time, print
1479 *     a warning only if we can reserve less than 10% of the expected amount of
1480 *     the reserved PEB.
1481 *
1482 * The idea is that when UBI is used, PEBs become bad, and the reserved pool
1483 * of PEBs becomes smaller, which is normal and we do not want to scare users
1484 * with a warning every time they attach the MTD device. This was an issue
1485 * reported by real users.
1486 */
1487static void print_rsvd_warning(struct ubi_device *ubi,
1488			       struct ubi_attach_info *ai)
1489{
1490	/*
1491	 * The 1 << 18 (256KiB) number is picked randomly, just a reasonably
1492	 * large number to distinguish between newly flashed and used images.
1493	 */
1494	if (ai->max_sqnum > (1 << 18)) {
1495		int min = ubi->beb_rsvd_level / 10;
1496
1497		if (!min)
1498			min = 1;
1499		if (ubi->beb_rsvd_pebs > min)
1500			return;
1501	}
1502
1503	ubi_warn(ubi, "cannot reserve enough PEBs for bad PEB handling, reserved %d, need %d",
1504		 ubi->beb_rsvd_pebs, ubi->beb_rsvd_level);
1505	if (ubi->corr_peb_count)
1506		ubi_warn(ubi, "%d PEBs are corrupted and not used",
1507			 ubi->corr_peb_count);
1508}
1509
1510/**
1511 * self_check_eba - run a self check on the EBA table constructed by fastmap.
1512 * @ubi: UBI device description object
1513 * @ai_fastmap: UBI attach info object created by fastmap
1514 * @ai_scan: UBI attach info object created by scanning
1515 *
1516 * Returns < 0 in case of an internal error, 0 otherwise.
1517 * If a bad EBA table entry was found it will be printed out and
1518 * ubi_assert() triggers.
1519 */
1520int self_check_eba(struct ubi_device *ubi, struct ubi_attach_info *ai_fastmap,
1521		   struct ubi_attach_info *ai_scan)
1522{
1523	int i, j, num_volumes, ret = 0;
1524	int **scan_eba, **fm_eba;
1525	struct ubi_ainf_volume *av;
1526	struct ubi_volume *vol;
1527	struct ubi_ainf_peb *aeb;
1528	struct rb_node *rb;
1529
1530	num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
1531
1532	scan_eba = kmalloc_array(num_volumes, sizeof(*scan_eba), GFP_KERNEL);
1533	if (!scan_eba)
1534		return -ENOMEM;
1535
1536	fm_eba = kmalloc_array(num_volumes, sizeof(*fm_eba), GFP_KERNEL);
1537	if (!fm_eba) {
1538		kfree(scan_eba);
1539		return -ENOMEM;
1540	}
1541
1542	for (i = 0; i < num_volumes; i++) {
1543		vol = ubi->volumes[i];
1544		if (!vol)
1545			continue;
1546
1547		scan_eba[i] = kmalloc_array(vol->reserved_pebs,
1548					    sizeof(**scan_eba),
1549					    GFP_KERNEL);
1550		if (!scan_eba[i]) {
1551			ret = -ENOMEM;
1552			goto out_free;
1553		}
1554
1555		fm_eba[i] = kmalloc_array(vol->reserved_pebs,
1556					  sizeof(**fm_eba),
1557					  GFP_KERNEL);
1558		if (!fm_eba[i]) {
1559			ret = -ENOMEM;
 
1560			goto out_free;
1561		}
1562
1563		for (j = 0; j < vol->reserved_pebs; j++)
1564			scan_eba[i][j] = fm_eba[i][j] = UBI_LEB_UNMAPPED;
1565
1566		av = ubi_find_av(ai_scan, idx2vol_id(ubi, i));
1567		if (!av)
1568			continue;
1569
1570		ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
1571			scan_eba[i][aeb->lnum] = aeb->pnum;
1572
1573		av = ubi_find_av(ai_fastmap, idx2vol_id(ubi, i));
1574		if (!av)
1575			continue;
1576
1577		ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
1578			fm_eba[i][aeb->lnum] = aeb->pnum;
1579
1580		for (j = 0; j < vol->reserved_pebs; j++) {
1581			if (scan_eba[i][j] != fm_eba[i][j]) {
1582				if (scan_eba[i][j] == UBI_LEB_UNMAPPED ||
1583					fm_eba[i][j] == UBI_LEB_UNMAPPED)
1584					continue;
1585
1586				ubi_err(ubi, "LEB:%i:%i is PEB:%i instead of %i!",
1587					vol->vol_id, j, fm_eba[i][j],
1588					scan_eba[i][j]);
1589				ubi_assert(0);
1590			}
1591		}
1592	}
1593
1594out_free:
1595	for (i = 0; i < num_volumes; i++) {
1596		if (!ubi->volumes[i])
1597			continue;
1598
1599		kfree(scan_eba[i]);
1600		kfree(fm_eba[i]);
1601	}
1602
1603	kfree(scan_eba);
1604	kfree(fm_eba);
1605	return ret;
1606}
1607
1608/**
1609 * ubi_eba_init - initialize the EBA sub-system using attaching information.
1610 * @ubi: UBI device description object
1611 * @ai: attaching information
1612 *
1613 * This function returns zero in case of success and a negative error code in
1614 * case of failure.
1615 */
1616int ubi_eba_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
1617{
1618	int i, err, num_volumes;
1619	struct ubi_ainf_volume *av;
1620	struct ubi_volume *vol;
1621	struct ubi_ainf_peb *aeb;
1622	struct rb_node *rb;
1623
1624	dbg_eba("initialize EBA sub-system");
1625
1626	spin_lock_init(&ubi->ltree_lock);
1627	mutex_init(&ubi->alc_mutex);
1628	ubi->ltree = RB_ROOT;
1629
1630	ubi->global_sqnum = ai->max_sqnum + 1;
1631	num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
1632
1633	for (i = 0; i < num_volumes; i++) {
1634		struct ubi_eba_table *tbl;
1635
1636		vol = ubi->volumes[i];
1637		if (!vol)
1638			continue;
1639
1640		cond_resched();
1641
1642		tbl = ubi_eba_create_table(vol, vol->reserved_pebs);
1643		if (IS_ERR(tbl)) {
1644			err = PTR_ERR(tbl);
1645			goto out_free;
1646		}
1647
1648		ubi_eba_replace_table(vol, tbl);
1649
1650		av = ubi_find_av(ai, idx2vol_id(ubi, i));
1651		if (!av)
1652			continue;
1653
1654		ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
1655			if (aeb->lnum >= vol->reserved_pebs) {
1656				/*
1657				 * This may happen in case of an unclean reboot
1658				 * during re-size.
1659				 */
1660				ubi_move_aeb_to_list(av, aeb, &ai->erase);
1661			} else {
1662				struct ubi_eba_entry *entry;
1663
1664				entry = &vol->eba_tbl->entries[aeb->lnum];
1665				entry->pnum = aeb->pnum;
1666			}
1667		}
1668	}
1669
1670	if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
1671		ubi_err(ubi, "no enough physical eraseblocks (%d, need %d)",
1672			ubi->avail_pebs, EBA_RESERVED_PEBS);
1673		if (ubi->corr_peb_count)
1674			ubi_err(ubi, "%d PEBs are corrupted and not used",
1675				ubi->corr_peb_count);
1676		err = -ENOSPC;
1677		goto out_free;
1678	}
1679	ubi->avail_pebs -= EBA_RESERVED_PEBS;
1680	ubi->rsvd_pebs += EBA_RESERVED_PEBS;
1681
1682	if (ubi->bad_allowed) {
1683		ubi_calculate_reserved(ubi);
1684
1685		if (ubi->avail_pebs < ubi->beb_rsvd_level) {
1686			/* No enough free physical eraseblocks */
1687			ubi->beb_rsvd_pebs = ubi->avail_pebs;
1688			print_rsvd_warning(ubi, ai);
1689		} else
1690			ubi->beb_rsvd_pebs = ubi->beb_rsvd_level;
1691
1692		ubi->avail_pebs -= ubi->beb_rsvd_pebs;
1693		ubi->rsvd_pebs  += ubi->beb_rsvd_pebs;
1694	}
1695
1696	dbg_eba("EBA sub-system is initialized");
1697	return 0;
1698
1699out_free:
1700	for (i = 0; i < num_volumes; i++) {
1701		if (!ubi->volumes[i])
1702			continue;
1703		ubi_eba_replace_table(ubi->volumes[i], NULL);
1704	}
1705	return err;
1706}